Device for increasing the usable luminous flux of fluorescent lamps



Feb. 1,1966 scHMlT-r 3,233,096

DEVICE FOR INCREASING THE USABLE LUMINOUS FLUX OF FLUORESCENT LAMPS Filed June 28, 1965 IN VENTOR /7E//VA /Cf/ SCH/711";

ATTORNEY United St tes Pa en 3 233 096 nnvrcn non INcRnAsrri THE USABLE LUMI- NDUS FLUX 0F FLUORESCENT LAMPS Heinrich Schmitt, Wilhelm-Leuchnerstrasse 87, Frankfurt am Main, Germany Filed June 28, 1965, Ser. No. 467,546 3 Claims. (Cl. 24051.11)

This application is a continuation-in-part of application S.N. 196,036 filed on May 16, 1962, now abandoned, by the same applicant.

The essential characteristic and effort in connection with heretofore known reflectors for fluorescent lamps was to reflect the light stream emitted from the surface of the fluorescent lamp directly into space.

The reflectors according to the invention differ basically from the heretofore known reflectors, by employing a mirror reflection of the light stream for reflecting in all directions without glare. By the term mirror reflection is understood a predominantly guided reflection.

According to the invention, this is effected by providing a reflector which is assembled from a pair of halves of cylindrical shape which surround the fluorescent light and which merge at their apices, so that the center points of a circle through a reflector cross-section are disposed interiorly of the fluorescent lamp, whereby the radius (R) of this circle is greater than the radius (r) and smaller than the diameter (2r) of the fluorescent lamp cylinder.

By this arrangement, the central axes of the partial circles, which likewise represent their burning axes, cut through the surface of the emitting cylinder of the fluorescent lamp, whereby there is effected a reciprocating action between the latter and the reflector.

In order to distinguish the basic underlying difference as against previous reflectors and likewise the differing effects of the reciprocal reflexive direction between the diffusing cylindrical surfaces of the fluorescent lamp and the attached reflecting bent surfaces, these have been given the designation of reflexive reflectors.

Accordingly, the entire reflecting surface of the illuminating reflexive reflectors is disposed in the burning surface which is reflected through the cylindrical surfaces of the tube according to the catacoustic effect.

The small thickness of the reflexive reflectors and their small weight make it possible to mount these as simple insert devices directly on the fluorescent lamp or on any desired lamps between the fluorescent lamp and the carrying fixture proper.

Plastic synthetic materials, e.g. methacyl acrylates, plastic polymer mixtures, are preferably used for the reflectors and their reflection surfaces are covered with completely reflective coatings.

The accompanying drawing illustrates schematically embodiment examples of the inventions, the details of which will be explained further.

In the drawing:

FIG. 1 is a schematic cross'section of a fluorescent tube with a bicylindrical reflexive reflector, illustrating the principle of the invention and FIG. 2 is a schematic representation of a construction form illustrating a pair of bicylindrical reflexive reflectors disposed relative to a fluorescent lamp.

In the schematic illustration according to FIG. 1, the light stream is shown in straight lines, parti larly in the right half of the figure. The light stream lines do not represent light rays, but show only the direction of the light beams, their widths as variously directed into space.

3,233,996 Patented Feb. 1, 1966 In the schematic representation of FIG. 1, the reflexive reflector 4 surrounds the apex 3 of the tube 1. The diffused stream leaving the tube, illuminates thereby the reflector 4. A part of the light rays leaving the reflector is again reflected on the tube and there effects an additional excitation and illumination of the fluorescent tube coating 2. The fluorescent tube coating limits again its increased light stream upon the reflector 4 on the one hand and on the other hand it illuminates the remainder of the tube by the increased inner light stream.

The continuous returning reflexive reflection takes place thereafter under the additional excitement of the fluorescent light tube until a final equilibrium takes place.

The effective openings of the reflector 4 produce parallel light bands on both sides of the tube.

Since diffused light streams are dealt with, there are observed, according to individual diameters of the tubes and spacing of the openings of the reflectors, common light bands of different intensity, e.g. 18, 19, 20, 21, for which there is now effective the Lambert conus function of diffusing bent emitting surfaces.

The smaller the space between the reflector and the tube 1, the greater is the mutual illumination and intensity and the smaller is, however, the width of the light band.

In the embodiment according to FIG. 1, the circular shaped reflector arcs 4 surround, in cross-section beginning at the zenith, the upper half of the fluorescent lamp 1. Radii R1 of the circular arcs are larger than the radius r of the lamp. The center points of the cycles are disposed inwardly of the fluorescent light tubes on the horizontal, through the longitudinal axis thereof.

In this embodiment example, the light bands mutually produced by the fluorescent lamp and the reflector cover have almost the same intensity in all light ray directions. The width of the light band 18 amounts to about twice the diameter of the map. The light bands 19 and 21 amount to the cosine of the opening of the reflectors. The light band 20 indicates the side radiation from the part of the adjacent fluorescent lamp 2, which is emitted from the surrounding reflector.

The reflexive reciprocating effect between the reflector and the lamp is also attained in this embodiment and thus results in the expression that with mirror reflection there are no dead Zones.

FIG. 2 illustrates the contours of a pair of bicylindrical shaped reflectors which merge into one another and define the limits of the effective area according to the invention. The partial circular arcs 23 and 24 which extend sideways from the Zenith of the fluorescent lamp encircle the lamp about its sides from the upper to about the lower edges. The corresponding centers M2 and M3 of the circles are disposed in each case interiorly of the cylindrical tube of the fluorescent lamp, i.e. interiorly of the fluorescent light coating. The radii R2 and R3 of the partial circular arcs are larger than the radius r of the lamp. As a result of these determinations, the radii of the partial arcs must be smaller than the diam.- eter 2r of the fluorescent lamp in order to make possible the production of reflexive reflectors. In general, the reflectors according to the invention are constructed in such a manner that they may be used as covers on exist.- ing installations of any kind without making any changes, e.g. they may be mounted on the ends of the fluorescent lamps on the sockets. They may also be made of syn.- thetic material, the surfaces of which are covered with a completely reflective coating.

I claim:

1. In a fluorescent light fixture provided with a cylindrical-shaped lamp, a pair of substantially semi-cylindrical mirror reflectors having adjacent edges merging with said reflectors being of thermoplastic material provided one another, the center points of the cross-section of each with continuous reflective coating. of said reflectors being disposed interi'orly of the crosssection of said lamp, the radii of each of said respective References Cited by the Examiner reflectors being greater than the radius of the cross-section 5 UNITED STATES PATENTS of the lamp and smaller than its diameter.

2.'In a fluorescent light fixture according to claim 1, s i wherein the centers of the cross-sections of the reflectors e c are disposed on a horizontal hne extending through the NORTON ANSHER Primary Examinen cross-section of said lamp. 1

O 3. In a fluorescent light fixture according to claim 2, C. R. RHODES, AsszstantExammer. 

1. IN A FLUORESCENT LIGHT FIXTURE PROVIDED WITH A CYLINDRICAL-SHAPED LAMP, A PAIR OF SUBSTANTIALLY SEMI-CYLINDRICAL MIRROR REFLECTORS HAVING ADJACENT EDGES MERGING WITH ONE ANOTHER, THE CENTER POINTS OF THE CROSS-SECTION OF EACH OF SAID REFLECTORS BEING DISPOSED INTERIORLY OF THE CROSS- 